And walter ferris



W. E. MAGIE AND W.`FERRIS. LEAKAGE REURN FOR HYDRAULIC TRANsn/nssloN.

APPLICATION FILED AUG.3. I9IBA Patented Aug. 12, 1919.

/Nm mwa h@ Sw W. E. MAGIE AND W. FERRIS.

LEAKAGE RETURN FOR HYDRAULIC TRANSMISSION.

APPLICATION FILED AUGIS. I9IB.

l ,3 1 2,70 l Paten'red Aug. 12, 1919.

3 SHEETS-SHEET 2.

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APPLICATION FILED AUG.3. I9I8, 1,312,701.

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UNITED sTA'rns PATENT ormoni.

WILLIAM E. MAGIE, OF BUFFALO, NEW YORK, AND WALTER FERRIS, OF MILWAUKEE,

WISCONSIN.

LEAKAGE-RETURN FOR HYDRAULIC TRANSMISSION.

Specification of Letters Patent.

Patented Aug. 12, 1919.

vApplication led Aug-ust 3, 1918. Serial No. 248,178. I

.ment in Leakage-Returns for Hydraulic Transmissions, of which the following 1s a speciication. c

Our invention relates to hydraulic power transmission devices such as indicated on the accompanying drawingsbut we do .not wish 'to limit ourselves to any one particular construction as our arrangement for leakage return herein embodied, with slight modification, is adaptable to other forms o f mechanism which are in service as hydraulic power transmissions.

The objects of our invention are to aford ample opportunity for' sedimentation of the oil which leaks beyond the pressure circuit before returning same thereto; also to provide means for suliicient de-aeration ofthe oil or other fluid used; also to afford a mechanism which will .produce a pressure higher than atmospheric pressure in returning the working fluid to the pressure, circuit, thus reducingthe tendency to ebullition in the 'luid and retarding the emulsification of the said working iii-iid; also to provide anarrangement whereby the working fluid used may be conveniently inspected as to its clarity and general condition before and after having passed through the Working parts of the machine; also to provide a pumping system actuated by a moving part of the transmission device for returning at least a part of the leakage; also to provide means by which the returned fluids are injected back into the pressure circuit evenly, keeping a constant head behind the pressure circuit and avoiding, in doing so, any pulsating or throbbing effect in the working fluid employed.

Our. invention is illustrated more or less diagrammatically in the accompanying drawings wherein- Figure l is an end view inppart section and with some parts broken away;

Fig. 2 is a section on line 2-2 of Fig. 1 with parts in elevation;

Fig. 3 isA a section along line 3e-3 of Fig. 2 with parts omitted; p Y

Fig. 4 is an enlarged detail sectional view of pump assembly;

Fig. 5 is an enlarged detail sectional view of the distributing valve block;

Fig. 6 is a section taken on line 6-6 of Fig. l;

Fig. 7 is a sectional view of the central assembly.

Like parts are indicated by like characters in all the drawings.

C is a'casing which contains a main or power pumping mechanism driven by an external source of power through a shaft S. It also contains a stroke changing mechanism whereby the stroke and displacement of the pump may be changed at the will of the operator and the hydraulic motor of similar construction to the pump which motor is driven by. fluid discharged by the pump thereby generate ypower which is transmitted through the shaft S1.

The pump comprises a driving disk D -mounted upon shaft S, a group of pumping plungers actuated by said drivin disk, and a multiple cylinder barrel D2 1nto whose cylinders said plungersare fitted, but which is mounted upon a pintle formed upon a sliding pintle block Z, whereby the eccentricity of pintle may be varied. A

The stroke changing mechanism comprises the sliding pintle block Z, a stationary crossI rail T supporting said pintle block and a hand wheel orother suitable mechanism for controlling the sliding of said pintle block, and consequently' varying the stroke and displacement of pump.

The hydraulic motor comprises a stationary pintle formed eccentrically upon the cross rail T and similar to the sliding pintle already alluded to as forming p art of the pump, a multiple cylinder barrel D3 mounted upon said stationary pintle and similar to corresponding cylinder barrel of the pump, a set of 'motor vplungers D5, and a ldriven disk D1 actuated by the fluid pressure generated by the pump and acting against plungers D5 whereby poweris generated in said crank disk D1 and transmitted by shaft S1 to which this crank disk is attached.

The preceding parts are not fully indicated in the drawings and are not described in detail as they are parts of a typicalv hyldraulic transmission mechanism and do not comprise any part of thevpresent invention.

The sliding block Z is supported by the stationary cross rail T and has a smooth rail engaging contact face, in which are formed two pairs of communicating elongated ports 41,. 43 and 42, 44, which form elements of a double system of ports and passages connecting the main pump with the hydraulic motor, and serving to transmit working fluid. Either port may be under high pressure, the other being under low pressure. A continuous drain groove 45 cut in the face of sliding block Z surrounds ports 4l, 43 and 42 44. This groove intercepts all leakage from the ports, 'in the sliding faces instead of permitting it to escape into the interior of the casing. An annular groove 46 surrounds each plunger D5, intercepting all high pressure leakage past said plunger from interior of cylinder. Each groove 46 vcommunicates through a radial duct 47 with an annular gathering groove 48. Groove 48 `has the function of gathering vall of the leakage returning through the ducts 47 from the intercepting grooves 46 around the plungers. It has also the function of interceptin leakage escapinglaterally ,(on the right hand as shown in Fig. 7) from the abutting surfaces of revolution between the interior bore of the cylinder barrels D3 D2 and their corresponding pintles. Groove 55 is located symmetrically with groove 48 but on the opposite side of the central plane of the cylinder barrel, and serves to intercept leakage escaping laterally (toward the left hand as shown in Fig. 7) between the abutting ported surfaces of the cylinder barrels upon the pintles. This leakage is returned tothe duct 49through duct 56. The ducts 49, 50 and 56 -connect grooves 48 and 55 with groove 45, these grooves forming a closed system receiving only oilrwhich has leaked past working surfaces under pressure. Two ducts 51 and 52 conductthis leakage into two check valves 53, 54 opening respectively into the ports 43 and 44.

The high pressure existing in port 43 or 44' respectively will close .check valve 53 or 54 respectively leaving corresponding check -valve 54 or 53 respectlvely free to open and permit leakage in gathering groovesto return directly by its own pressure and without pumping or other mechanical assistance into the main circuit.

The lcasing C is closed by the end heads E and E1 havin respectively the integral eX-' tensions or hu s H and H1 for the mounting of suitable bearings for the centrally located shafts S and S1.

The end head E is formed with a divided reservoir R to contain a portion of the work- 'ing fiuid which for the moment is not within the active fluid circuit of the power transmission, but1 is in reserve. This reservoir is integral with end head E and surrounds hub VH in annular form, the hub passing through the 'annular reservoir and serving in connection with partition X and its enlargement B to divide reservoir intotwo sections 10 and 11 which communicate with each other onlyv over the upper part of hub H. This construction permits the introduction of oil into the lower part of compartment 10 as hereinafter described, and the removal of said oil from'reservoir through an opening in the lower part of compartment 11 thus compelling all oil so removed to pass over the upper edge o f hub H where it can be inspected before rentering the main circuit. Overflow pipe l2 as hereinafter described determinesthe oil level inreservoir R and inspection at this point will also reveal deficiency of the proper amount of oil in the apparatus, as in such case oil level will be below top of overflow pipe.

A catch basin R1 is formed inH the bottom of casing C by a curved partition P which closely conforms to the periphery of the disks D and D1. This partition P makes a tight junction with the ends of main casing but openings R2 are left at the sides of the casing through which oil may enter the catch basin.

The machine is charged with a quantity of oil sufficient to fill the working cylinders `main circuit of the machine it is immediately replaced by an equal quantity of oil forced inl as hereinafter described by pump G.y This leakage replacement is taken from compartment 11-of reservoirvR and is im mediately replaced by an equal amount of oil flowing across top of hub H from left to right. A somewhat larger quant-ity of oil is simultaneously pumped through a different set of passages -fby same pump G from catch basin R1L into Ithe lower part o f compartment 10 of reservoir R. This larger quantity of oil rises slowly through the left hand compartment 10 of reservoir to the surface in the neighborhood of upper end of overflow pipe 12 and divides into two parts; an amount exactly equal to the amount simultaneously withdrawn from compartment 1l to supply leakage from the power circuit passes over the top of the hub H on the right hand side of reservoir, while all excess above said amount flows into the top of the overflow pipe 12 and returns into the catch basin through port 13, to be' again pumped up by the pump assembly G as hereinafter described. f

The pump' G really comprises two sepa'- rate pumps having the common ,plunger 2- closely fitted in the pump cylinder. as shown,

the upper end of said pump cylinder. Tubular extension 3 is pin connected to a rod 4 which engages a crank lpin formed on the end of crank shaft 5 to which shaft is keyed gear wheel 8 meshing with gear wheel 9 which is secured to main pump shaft S. Therefore the pump G is continuously operated so long as the power pump is in operation. The two separate parts of the pump in this assembly are the circulating pump and theleakage return pump.

Circulatin pump G1 is formed by the lower end o plunger 2 coacting with the lower end of the pump cylinder, taking in oil through inlet opening 1 from reservoir R1 and discharging through check valve V and passage through tubular plunger extension 3 into crank case 6 and thence through port 7 which terminates in bottom of compartment 10 of reservoir R.

The leakage return pump is formed by the upper end of the plunger 2 coacting with the upper part of the pump cylinder bore taking in oil through the passage 14 communicating with lower part of compartment 11 of reservo-ir R on the right hand side of partition X, and discharging through port 15, check valve 17 and pipe 16. Pile 16 divides into a leakage return pipe 30, which supplies to the main power circuit the exact amount of make-up oil required, and the side branch 21 which discharges into reservoir R through relief valve body 22. Through this relief valve a predetermined pressure is maintained on a leakage return system and the excess oil not required to make up the deficiency caused by leakage is returned to reservoir R- to be again circulated. l

The intake passages 1 and 14 respectively of the circulating pump G1 and the leakage return pump G2 respectively are opened and closed by the travel of the pumpplunger 2, each intake poi-'t being opened as the plunger approachesthe end of the coresponding suction stroke and closed soon after the plunger starts on its return or delivery stroke; aften which closure of the intake port the remaining fluid is expelled/through the delivery check valve V or 17 respectively As already described the mainipower pump and the motor jare connected by a closed system of ports, one side ofthe system -carrying highpressure fluid from pump to motor and the other side carrying back to the pump low pressure or return iuid exhausted from the motor. When the hydraulic motor is reversed in direction the two sides of this closed port system interchange their functions, the former pressure port becoming the return port and vice versa. In Fig. 7, 32 indicates the port which is functioning as pressure port and which is at all times connected through passage and pipe 20 with the top side of distributing valve casing 18. 31 indicates the port functioning as low pressure or return port and connected through passage and pipe 2O with the right hand end of valve casing 18. As already mentioned leakage return pump G2 is contincheck valve 17 of this leakage return pump.

Relief valve 22 also serves to return into reservoir R all of the excess oil delivered by leakage return pump abovethe amount which which can pass into distributing valve 18 through leakage return pipe 30, are

`drilled through the shell of casing 22 to permit the escape into the reservoir of any fluid l which passes valve seat 211.

Oil can only pass into valve seat bypushing Ythe stem 26 to the right against the spring force until the left hand edge of plunger portion 31 passes the corner or the valve seat 24. The valve then begins to open and further compression of the spring will enlarge the annular opening so much as to permit the escape into reservoir R of 'any therefore the pressure against fluid in pipe lexcess in the delivery of leakage return 30 and its connecting passage to port 31 would be permittedv to fall momentarily unless other means than the leakage pump were supplied to avoid this. This function is supplied by the plunger portion 31 of relief valve which continues its motion toward the left should there be any fall i`n pressure in pipe 21 after edge of plug 31 has passed corner of conical valve seat. 1n this wayrelief valve plunger acts as an auxiliary pump plunger supplying momentarily the leakage f rom port 31 during each suction stroke of the leakage return pump and thus maintaining an even flow of returned leak: age under continuous 'pressure The use and operation of` Our invention are as follows:

Thepamount of power which may be transmitted by a hydraulic transmission of the type herein described is direetly prOpOri tional to the speed at which the machine can be run, and to the pressure which it will endure in the main oil circuit. This pressure is a function 0f the strength of the various parts, but the speed attainable depends principally upon the effectiveness of the devices for returning to the main oil circuit the oil which leads therefrom past the various working surfaces. In most hydraulic transmission machines the amount of this leak-v age which escapes into the casing increases Y rapidly with rising operating pressure, and.V

the leakage return pump or other device has .to have suicient capacity to return the the casing with rising operating pressure isl obviated by the intercepting grooves 461 around the various plungers, 45 around the abutting ports, and 48 and 55 around the interior bores of the cylinder barrels. All of the leakage from the ports, working cylinders, etc., subjected to high pressure is caught by the above described intercepting grooves and directly returned through either of the-check valves 53 or 54, as the case may be, into that port (43 or 44 as the case may be) which is conducting the eX- haust fluid from the hydraulic motor back to the intake port of the main pump, and is hence subjected only to low or return pressure.

The only fluid which leaks out into the casing is such as is forced past the abutting surfaces 60, 61, 62, 63 between the various working parts exterior to the various intercepting grooves. As all of these intercepting grooves are filled with fiuid at the revturn or low pressure which is almost oonstant, the quantity of this leakage into the p casing is small because the pressure is low Yand practically constant because the pressure is constant. The leakage return pump G2 may therefore be much smaller than the prevailing forms of hydraulic transmission and will always be running at approximately its full capacity as it does' not have to take care of peak loads of excessive leakage during periods of maximum working pressure.

Oil leaking from the main pressure circuit, cylinders, etc., of the main pump and hydraulic motor is either thrown outward against the to end walls of (casing C or falls downward into thecurved depression above partition P. The part which strikes the walls mayx -ldrain directly down into catch basin through openings R2. The part which strikes the cover may fall down on top of partition P. All oil gatheredvin partition P is continuously wiped up by disks D and D1 and thrown outward, striking the walls and draining down into the catch basin-R1. Thus all of the direct leakage is finally drained into the catch basin, where it is comparatively quiet. Sedimentation is thus assisted, most of the solid matter being deposited on the bottom of the catch basin as a sludge. Entrained air also tends to be disengaged from the oil comlng to the surface in the catch basin.

Circulating pump G1 continuouslyl draws from the comparatively Aquiet oil in the catch basin an amount greater than is necessary to supply the maximum leakage requirement. This oil is delivered into compartment l0 of reservoir It and slowly rises to the surface.

`During this process further sedimentation pressure an automatic occurs and further detrainment of air, the latter escaping in bubbles at the surface. Simultaneously leakage return pump G2 is continuously drawing from compartmentll a less quantity of oil than is being continuously. pumped into compartment 10 from vcatch basin. In the construction here shown the less displacement necessary for pump G2 is secured by usingthe upper part of pump chamber for this function, the displacement per stroke being reduced by the cross secl mentation and de-aeration of the working fluid.

l/Ve claim:

1. In 'a hydraulic transmission comprising a pump aunotor, and an oil circuit connecting and including them having both high and low pressure branches, means for intercepting leakage from the high pressure system and automatically returning it to the low pressure system together with separate means for positively supplying makeup oil to the low pressure system under 'pressure.

2. In a hydraulic transmission comprising a pump, a motor, and lan oil circuit connecting and including them having both high and low pressure branches, 'means for intercepting leakage from the high pressure system and automatically returning it to the low pressure system together with separate means for positively supplying makeup oil `to the low pressure system under pressure release adapted to permit escape of said oil when the pressure in the low pressure-system- `exceeds a predetermined point.

them, means for intercepting leakage from the high pressure system before it escapes into thehousing, means for conducting such f leakage back to the low pressure system and separate'means for positively returning oil which has escaped beyond the first intercepting means under pressure back into the low pressure system said means comprising a pump driven from the transmission pump.

5. In a hydraulic transmission comprising a pump and motor, an oil circuit connecting and including them having high and low pressure branches, a housing containing all the parts, means for intercepting leakage from the high pressure system, returning it automatically to the low pressure system and separate means for gathering the leakage from the interior of the housing and returning it under pressurel to the low pressure system. f

6. In a hydraulic transmission comprising a pump and motor, an oil circuit connecting and including them having high and low pressure branches, a housing containing allv the parts, means for intercepting leakage from the high pressure system, returning it automatically to the low -pressure system and separate means for gathering the leakage from the interior of' the housing and returning it under pressure to the low pressure system said means comprising a pump driven in unison with the transmission pump.

7. In a hydraulic transmission comprising a pump and motor, an oil circuit connecting them and having high pressure and low pressure branches, an empty casing, a catch basin, a reservoir, means for circulating reserve oil between the catch basin and the reservoir and means for forcing back into the oil cirf cuit suliicient oil to replace the leakage therefrom.

8. In a hydraulic, transmission comprising a pump and a motor, an oil circuit connecting them and'having high pressure and low pressure branches, a sedimentation reservoir, an inspection reservoir, means for transferring sedimented liquid to the inspection reservoir and means for returning make-up liquidto the active oil circuit.

9. In a hydraulic transmission, means for gathering and returning leakage comprising a reservoir divided into two parts, means for introducing leak-age into one of said parts and for drawing make-up oil from the second and forcingit back into the systhe leakage return means.

tem and means for inspecting said oil during its passage through the reservoir.

10. In a hydraulic transmission an empty operating chamber, a sedimentation basin for gathering leakage, means for returning leakage to the activecircuit and means for inspecting` said returned oil on its way to 11.4 In a hydraulic transmission, an empty operating case, a catch basin or sedimentation reservoir, means for conducting to the sedimentation reservoir leakage gathered in y the operating case and means comprising a pump for returning said oil from reservoir to main circuit.

12. .In a hydraulic transmission having a fluid pump and motor and high pressure and low pressure passages connecting them, a closed duct arranged to intercept leakage from the high pressure side of the oil circuit and to return it to the low pressure side, a chamber arranged to, gather all leakage not intercepted by said duct and a pump for returning said secondary leakage from said chamber to the low pressure side of circuit.

13. In a hydraulic transmission having a fluid pump and motor and high pressure and low pressure passages connecting them, a closed duct arranged to intercept leakage from the high pressure side of the oil circuit and to return it to the low pressure side, an operating chamber arranged to gather all leakage not intercepted by said duct and means for returning t0 low pressure side of the circuit at a pressure above that of the atmosphere said leakage gathered in the operating chamber.

14. Ima hydraulic transmission having a Huid pump and motor, and high pressure and low pressure passages connecting them, a closed duct .arranged to intercept leakage from the high pressure side of the oil circuit and return it to the low pressure side, a splash chamber arranged to gather all leakage not intercepted by said duct, and means foi` returnin to the low pressure side of 'the circuit all eakage gathered in the splash chamber.

15. In a hydraulic transmission having a' pump and amotor, a drainage groove located between adjacent working surfaces for gathering primary leakage and returning it 'fluid pump and motor, and high and low pressure passages connecting them, means for intercepting leakage from the high pressure side and returning it directly to the low pressure side of the oil circuit.

18. In a hydraulic transmission having a fiuid pump and motor, and high, and low pressure passages connecting them, a passage arranged to intercept the leakage .from the high pressure side of the oil circuit and to returnit directly to the low pressure side,

together with means for gathering all leakage' not intercepted by said passage, and rel turning it-to thev low pressure side of the circui l 19. In a hydraulic transmission having a Huid pump and motor, and high and low pressure passages connecting them, a passage arranged to intercept the leakage from the high pressure side of the oil circuit and to return it directly to the low pressure side, together with means for gathering all leakage not intercepted by said passage, and returning it under pressure to the low pressure side of the circuit.

20. In a hydraulic transmission having a fluid pump and motor, and high and low pressure passages connecting them, a passage arranged to intercept the leakage from the high pressure side of the oil circuit and to return it directly to the low pressure side, together with means for gathering all leakage notY intercepted by said passage, and re'- turning it under pressure to the low pres sure side of the circuit, comprising, in part, a' pump.

21. In a hydraulic transmission having a kday of July, 1918.

fiuid pump and motor, and high and low pressure passages connecting them, a passage arranged to intercept the leakage from the high pressure side of the oil circuit and to return it directly to the low pressure side, together with means for gathering all leakage not intercepted by said passage, and returning it to the low pressure side of the circuit comprising a pump and passages connected therewith, a liquid storage tank fed by the pump, and aI connection between said tank and the low pressure side of the circuit. Signed at Bualo, New York, this 23rd day of July, 1918.

WILLIAM E. MAGIE. Vitne'sse's for William E. Magie:

S. S. FRENCH, W. A. CHARLTON.

Signed at Milwaukee, Wisconsin, this 15th WALTER FERRIS. Witnesses for Walter Ferris;

META SCHMOLLER,

GEO. H. RoNDEAU. 

